Barely more than two weeks after her first child, Xander Dane Jones, was born on Sept. 13, the actress, 33, was seen out and about with him – and back in beautiful shape.

As for how her maternity might play out on the new season of the AMC hit, costar Jon Hamm, 40, told PEOPLE at this past weekend's Rape Foundation Annual Brunch, hosted by the cast of Mad Men: "I'll let you see that when you see it, but she is no longer pregnant. She has had a baby, and she's very excited and happy and healthy. Both sides are very healthy and happy, which is very sweet."